The proposed Stellenbosch University Clinical Trial Unit (SU CTU) is located at Tygerberg Academic Hospital, a tertiary care centre in Cape Town, South Africa. The metropolitan region has a high prevalence of HIV (13% of women attending antenatal clinics) and also a high incidence of tuberculosis (>600 new cases/100 000 population). The SU CTU has three Clinical Research Sites (CRS) that operate in a well integrated fashion and an established referral system from regional hospitals, community health clinics and mid-wife obstetric units. The Children's Infectious Diseases (KIDCRU) CRS and the Prevention of Mother-to-Child Transmission (PMTCT) CRS were established through the Pediatric AIDS Clinical Trial Group (PACTG) and presently recruiting subjects into three transition studies (2 pediatric and 1 PMTCT). One pediatric study determines the role of isoniazid in preventing tuberculosis (P1041). The PMTCT study addresses the optimal time for HIV testing for pregnant women presenting for labor (P1031). Both studies will accrue subjects in the transition phase in excess of the 20 patient average per month required for each site. The KIDCRU CRS is planning two additional transition studies: 1. Antiretroviral (ARV) strategy trial which will provide critical information for the national ARV program (P390) and, 2. Hepatitis B vaccine study for adolescents, which will provide useful information and a nucleus for an adolescent research program (ATN024). The KIDCRU CRS; and PMTCT CRS have been invited to affiliate with the IMPAACT Network. The SU CTU has the support of expert consultants in adolescence, neonatology, childhood TB and pediatric neurology from the SU Faculty of Health Sciences, who will contribute to protocol development and study implementation. The third site is an Adult infectious Diseases Clinical Research Site (AIDs CRS). Although not yet affiliated with a HIV/AIDS network, its investigators have a track record of conducting ARV trials for industry and initiating a trial comparing two non-nucleoside reverse transcriptase inhibitors as a third component of ARV therapy. This CRS proposes an optimization study of immediate versus deferred initiation of antiretroviral therapy for HIV+ adults treated for tuberculosis (AACTG A5221). A co-mentoring partnership will be established with Dr. Thomas Campbell from the Colorado AIDS CTU, University of Colorado, and Prof. James Mclntyre, Perinatal HIV Research Unit ACTG, Witwatersrand University. Though this co-mentoring partnership, the AIDs CRS is expected to be able to enroll subjects within six months of funding. ADMINISTRATIVE COMPONENT: